I've only had one saw with flippy caps. An MS260. I liked the flippy caps for the most part until one day I overfilled the bar oil and absolutely could not get the damn thing back on. It didn't just make a mess, it actually would not go in due to hydraulic pressure. When I finally dumped some oil out, making a bigger mess, the cap still wouldn't lock because the little locking disc was in the wrong position. Fiddled with it some more and then it was fine. Lesson learned.
All of my other Stihls have screw caps, which I prefer.
All of the older style screw caps, with the finer ridges, have cracked on me at some point and been replaced with the newer style.
I don't think those caps would have cracked were it not for over tightening with a scrench.
Does anyone know of a cap with big finger grips or knobs that will fit Stihl saws?